#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
    const char *before_v = "10";
    const char *after_v = "11";

    setenv("ABC", before_v, 0);

    setenv("ABC", after_v, 0);
    printf("getenv = %s\n", getenv("ABC"));

    setenv("ABC", after_v, 1);
    printf("getenv = %s\n", getenv("ABC"));
	return 0;
}
